Proportional pressure doubleacting power amplifier



May 29-, 1951 E. G. STAUDE I PROPORTIONAL PRESSURE DOUBLE-A'CTING POWER AMPLIFIER 1'7 Sheets-Sheet 1 Filed July 51, 1945 --anamg|| INVENTOR Edwin Sauaie BY a w ATTORN Filed July 51, 1945. I v 17 Sheets-Sheet 2 May "29, 1951 E. G. QSTAUDE 2,554,843

-- PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER INVENTOR v Edwinj.5iaucle BY W I- ATTORN Y 2,554,843 I PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed July 31,

May 29, 1951 E. s. STAUDE l7 Sheets- Sheet 4 INVEN TOR Edwin Stazwie Filed July 31, 1945 '1'? Sheets-Sheet 5 y l951 E. G. STAUDE 2,554,843

PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER INVENTOR Edwin Saua'e ATTOR Y E. G. STAUDE 2,554,843 PROPORTIONAL PRESSURE bouBLE-Acmc POWER AMPLIFIER May 29, 1951 l"! Sheets-Sheet 6 Filed July 51, 1945 I Edwzn 9 Siaude ATTORR Y i I wud I v III Emmi A 3 7 4 t R E 8 e 0 N m M M 5 s T 2 m w mh m m w k m n M m w Q P a? G m w g A fiwMW'KE 1/ m W. & G. W Q M6 ow S mm, .vfi L Q &\ m w: n hm, w a v X R V mw y w b v a l 1 4 E. G. STAUDE May 29,1951

' PROPORTIONAL- PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed July 31, 1945 17 Shegts-Sheet 8 INVENTOR E. a. STAUDE May 29, 1951 PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed Jul'y 31, 1 945 17 Shets-Sheet 11 INVENTOR y- Si-aude Eclwin o I Q I ATTOR Y May 29, 1951 E56. STAUDE 2,554,843

PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed July 31, 1945 17 Sheqts-Sheet 12.

T1 BE:

" INVENTOR Ed" .sauaz 2// I ATTORNEY E. G. STAUDE May 29, 1951 PRQPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER l7 Sheets-Sheet 15 Filed July 31, 1945 INVENTOR 9. S'agzd ATTORNE Edwin w Qw May 29, 1951 2,554,343

PROPORTI ONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER E. G. STAUDE 1'7 Sheets-Sheet 14 Filed July 31, 1945 INVENTOR Saude ATTW May 29, 1951 E, (31 STAUDE 2,554,843

PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed July 51. .1945 1'? Sheets$heet 15 INVENTOR ATTORfiY y 1951 r E. G. STAU DE 2,554,843

PROPORTIQNAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER I Filed July 31, 1945 I7.Sheets-Sheet 16' I I Q) N v 2 ATTO EY May 29, 1951 E. c;. STAUDE PROPORTIONAL PRESSURE DOUBLE-ACTING POWER AMPLIFIER Filed July 51, 1945 1''! Sheets-Sheet 17 4. Lil

INVENTOR Edwin Patented May 29, 1951 PROPORTIONAL PRESSURE DOUBLE- ACTING POWER AMPLIFIER Edwin G. Staude, Minneapolis, Minn, assignor of one-half to Olive Bertha Staude, Minneapolis, Minn.

Application July 31, 1945, Serial No. 607,945

20 Claims.

1 My invention is particularly applicable to assist in the manual operation of the rudder, elevators, ailerons, or landing brakes of airplanes,

or for steering gears or brakes on motor cars, busses, etc., although it is capable of many other different fields of utilization.

My invention is, also, particularly desirable in airplanes which fly at high altitude, because the fluid being a very low-freezing liquid and in continuous circulation, keeps the device from the freezing which has frequently occurred previously in other devices where compressed air has been used.

This invention is an improvement over my copending application upon Double Acting Proportional Pressure Power Amplifier, Serial No.

513,647, filed December 8, 1943, Patent No. 2,5l65,761, granted March 29, 1949, wherein I use a system of a single fluid circulating medium and wherein a part of the built-up pressure reacts against the control lever to obtain the performance feel, so that the operator will always have a definite control and a sense of the increased stroke and pressure required for the work to be performed, whereas in my present invention I use a second set of valves to distribute the flow in both directions from an inactive neutral position for distribution and uniform flow in each of the directions of motion of each of the valves.

I have obtained a pressure feel control in .my' earlier patent, Patent No. 2,095,841, granted event of failure of the fluid circulating system.

In my copending application aforesaid and in this present application, which have to'do with an apparatus, I utilize this same reverse mechanism, but so that it acts in both directions from a neutral central position, in a valve control such as shown in my Patent No. 2,095,841, aforesaid. I have found this to be highly efficient, except that I now adapt this reverse mechanismtoact in both directions, inasmuch as my preceding and present amplifier are double acting, that is to say, operable in either direction,'whereas the reverse mechanism shown in my Patent No. 2,095,841 operates only in one direction, relying on retractor springs toreturn the mechanism to its starting point. This invention comprises the broad idea of a single fluid inlet and a single fluid outlet with two circuits interposed between them. It contains a double acting device, such as a piston or vane to perform work, against which fluid under pressure acts and with which two fluid circuits are provided having single or separate fluid inlet and outlet passages, but which are provided with fluid controlling valves operating simultaneously to obtain fluid pressure in one circuit to perform work and open the circuit in the other passage to exhaust the fluid on the other side of the means against which pressure acts to perform work. Thereby, the degree of movement or work to be performed is controlled through the amount of fluid pressure admitted by the valves and, thereby overrunnin of the work to be performed is prevented by connections between the surfaces against which pressure acts and the valve seats or sleeves.

This device, for example, is illustrated herein as a double equal-acting fluid power actuator which uses a single source of fluid and divides the circuit into two circuits leading to two chambers and returns the same to the source of power with twodistributor valves to distribute the flow .and two reacting valves operating against pressure to provide the reaction pressure.

The two distributor valves divide the flow to the respective work performing elements which are movable walls whereby when in neutral or center position two equal flow circuits result.

A shift of both said distributor valves in either direction will cause decreased flow in one circuit and increased flow in the other which flow. in each case is connected to the appropriate movable Wall or work performing element which is interposed between the respective distributor valve and the reaction return flow Valve.

The reactionary valve takes the increased flow from the movable wall and by movement restricts the outflow by opposing the flow of the circuit against pressure which reacts against the valve control means.

The proportionate increase of pressure reacts against the work performing element or movable wall while the action of the opposite reaction valve works in reverse to decrease the exhaust pressure proportionately whereby complete control of the movable wall is maintained at all times, while at the same time the unbalanced pressure has a tendency to return the four valves to neutral by the action of the control of the flow of the fluid in the two circuits.

While one circuit becomes the pressure circuit the other becomes the exhaust circuit both of which are always under the control of the valve control means.

By using the four valves and the two fluid circuits I am able to increase the pressure in one circuit and at the same time proportionately decrease the pressure in the other thereby preventing over-running and at the same time maintaining perfect follow up in both directions of operation with the motion of the valve controlling means.

The fluid passages and thecompartments in which the vanes or movable walls operate in accordance with my present invention are always filled with fluid under circulating pressure, so that the slightest movement of the valves in either direction creates an instantaneous pres- ..sure response, thereby preventing even the slightest lag or over-running.

'While I have shown a pump as an integral .part of my invention, it is obvious that it may be operated in any other convenient way. Also, the degree of assistance can be readily controlled by the pressure and the area against which the pressure fluid acts.

.One of the important objects of my invention is to counterbalance the pressures-onthe oscillating vanes of my double acting fluid power amplifier, so that the bearing or pivot of the vanes may carry only the load of the actual work performed.

A'further object is to .direct the fluid "when under pressure to the vanes equally on opposite .sides' .of the pivot of. both vanes to raid in the motion thereof in the same direction.

Another object is greatly to reduce the distance of'travel of the fluid from the output passage to the input passage of the pump, thereby greatly decreasing frictional losses and the attendant heat generated thereby.

Afurther object is to split the circuit for the liquid when the cruising circuit is beingused and then cause' the same to travel in passages connecting bothsides of the vanes when idling,

thereby providing, in effect, larger passages for 'the 'fiow of the fiuid and producing correspondreaction on the. manual control lever, for the purpose. of feeling the increase-1 in pressure.

A further object is '.to provide a'piston valve of small area whereby the pressure may be sealed off easily and made oil-tight when the amplifier is being operated by static pressure.

:Again, a further object is to provide a multiple poppet or piston valve which opposes the-pressure or the direction of fiuidflow.

Another object of my invention-is to provide .-a poweramplifierusing a. single pump with a single. inlet and a single outlet to and from the power unit, but with a split circuit .within the unit when in action, to provide-instantaneous response in onedirection as the other circuit is starting to close off by the action of the reverse motion valve control mechanism.

A further object is to provide an apparatus of this character of small size arranged to be operable at high pressure and which may be easily manufactured and assembled.

Other objects of my invention will readily appear from the accompanying drawings and specifications and the detailed description thereof.

While I show in the accompanying drawings a cruising circuit in which the fiuid is in continuous motion, I do notwish to limit my invention thereto as I may start the flud pressure generating mechanism by the initial movement of the control lever in a manner similar to that shown and described in my Patent No. 2,095,841 aforesaid, or- I may use static pressure for this purpose, as hereinafter shown and described.

Although my invention is intended to use a special very low-freezing point oil for the circulating fluid, I do not wish to limit my invention thereto'because to use compressed air or atmospheric pressure instead is merely a matter of adaptation thereof.

While my invention is capable of embodiment in many different forms, for the purpose of illustration I have only shown certain forms thereof in the accompanying drawings, in which:

' Fig. 1 is a front elevation of an apparatus made in accordance with my'invention;

Fig. 2 is a similar view from the opposite, side thereof;

Fig. 3 is a vertical section on a line'33 of Fig. 1;

Fig. 4 is a vertical section on the line 4-4 of Fig.3;

"Fig. 5 is a vertical section onthe line 55 of Fig. 3;

Fig. 6 is a vertical section on the line 6-6 of Fig. 3;

Fig. 7 is a vertical section on the line 7-1 of Fig. 3;

Fig. 8 is a horizontal section on the line 8-8 of Fig. 4;

Fig. 9 is a horizontal section onthe line 99 of Fig. 4;

Fig. 10 is a longitudinal section on the line Ill-I0 of Fig. 1;

Fig. 11 is a vertical section on line ll--ll of Fig. 4;

Fig. 12 is a vertical section. on line I2l2 of .Fig. 13 is a vertical. section ofthe valve .controlling levers on the line l3l3 of Fig. 2;

Fig. 14 is a. detail of the valve seat mounting shown in Fig. 9;

Fig. 15 is a vertical section on line [5-45 of Fig.'21 showing the passages of a modified valve constructionwherein the valves, instead of being of the poppet type, are piston valves, so as to adapt the system for use in connection with static pressure, thatis to say, where the fluidis not incontinuous circulation;

Fig. 16 is a vertical section on line l6|6 of Fig. 21. through the valve seat member and shows the valves in an extreme position;

Fig. 17 shows a. development in plan of the lower valve ports;

Fig. 18 shows a development in plan ofthe upper valve ports;

Fig. 19is a vertical section of the piston valves of Fig. 16 in neutral position, that is,.when the static pressure is sealed off by closing the ports Fig. 22 is a vertical section on the line 22-22 of Fig. 21;

Fig. 23. is a vertical section on the line 23-23 of Fi 21;

Fig. 24 is a horizontal section on the line 24-24 of Fig. 16; Fig. 25 is a horizontal section on the line 25-2 of Fig. 16;

Fig. 26 is a horizontal section on the line 2626 of Fig. 16; Fig.2? is a vertical section on the line 2l'-2'| of Fig. 16;

Fig.'28 is a vertical section on the line 2828 -of Fig.16;

Fig. 29 shows a view like Fig. 19, but with all the ports being capable of being uncovered simultaneously for use as a continuously cruising circuit like that required in Fig. 4;

Fig. 30 is a vertical section showing the application of my power amplifier, adapted for cylinder and piston auxiliary power;

' Fig. 31 is a vertical section on the line 3I3l of Fig. 30;

Fig. 32 is an end view of my amplifier, partly in section, showing the valve passages in section;

and

Fig. 33 is a side view, partly in section, of my power amplifier looking towards the control cables and showing the manner of mounting the oscillating members.

In the drawings, referring, first, to Figs. 1 to 14, I have shown two cables l and 2, which are preferably one continuous cable, connected to any desired manually movable control element (not shown) in the cockpit of an airplane. These two cables I and 2 are connected to bifurcated socket members 3 and 4, respectively, which are pivoted by means of pins and 6 to the upper end of a lever l. The lever l is pivotally connected by a bolt 8, having a nut 9, to a main lever [0. On the bolt 8 there is also a link ll, having sockets l2 and I3 which are connected, respectively, to cables [4 and I5 which lead to any desired part to be moved--as, for example, the rudder of an airplane. The cables l4 and [5 lead to the opposite sides of said rudder so they will respectively move the said rudder in the desired direction when operated manually from the cables I and 2. It will be understood, likewise, that cables! and 2 are operated simultaneously in the same direction.

' By pulling on the cable I, this causes the part to I be moved to operate in one direction, and a pull on the cable 2 will cause the part to be moved in 4 the opposite direction, both cables being operable manually from a movable control element, which, in this particular instance, may be foot pedals (not shown) which are located in the airplane cockpit. It will, also, be noted that the cable I, whenactuated manually, willmove the cable partly manually and partly by power, the forces from both of which exert a movement in the same direction. Likewise, a pull on the cable 2 will, also, result in the partial manual power pull on the cable I4 in the opposite direction.

On the side of the lever I0 there is a centering device, normally keeping the manual control in middle position when not being actuated and restoring the manual control to middle position, comprisin a boss 16 (see Figs. 2 and 13) on which is mounted, by means of a pivot ll, a link [8 through which passes a rod l9, having a head 20,

' secured within an ear 2| on the lever H), the other end of which rod l9 has a nut 22 supported We compression spring 23, one end of which rests I against the side of the link l8. At the upper end which is keyed to a central shaft 34 and to which it is fastened by a split hub 35 having a bolt '36 fastened thereto and provided with a nut 31 (-se Figs. 2 and 3).

This central shaft 34 is located within a sleeve shaft 38 on which the lever I0 is keyed and fastened by a split hub 39 having a bolt 48 with a nut 4i thereon. A washer 42 is located between the levers 33 and ill. As shown in Fig. 3, the lever 33 is fastened to its shaft 34 by akey 43, and the lever it is fastened to its hollow-member 38 by a key 44. The shaft 34 and hollow member 38 are supported within anend plate 45 so as to pass through a chamber 46 within a casing and then through a cover plate? 48. The

end plate 45 and the cover plate 48 are clamped to the casing 41 by bolts '13 secured by nuts 14. Referring to Fig. 3, the cover plate 45 is provided with a bearing 49, and the cover plate 48 isp'rovided with a bearing 50 for the hollow .member 38. The oscillating hollow member. 38 :has a flange member 5| and is located adjacent. .to .a bored oscillating member 52, to facilitate the .assembling of the valve control mechanism hereinafter described. The two members 5| and 52 are held together by a cap-screw 53, tapped into the part 52, and a cap-screw 54, tapped into the part 5! (see Fig. 10). The cap-screws may be held in position by lock washers. Suitable dowel pins 55 and 56 are provided so that the member parts 5! and 52 will always fit together 1 in exactly the same position upon being taken apart and again reassembled.

Both of the members 5i and 52, which oscillate together with the oscillating member 38, are provided with vane-like projections 51 and 58 (see Figs. 4, 5 and '7), which. fit accurately, but ;-are free to move, within the inner surface of the wall 46 of the casing 41. Suitable partitions 5S and 6 3 are secured within the chamber by bolts 6! and 62 and dowel pins (not shown) to; divide the chamber into chambers which may be called compartments 63, 64, 65, and 6'6.

The valve or fluid-controllingstructure comprises a spider 6"! accurately fitted over a hex portion 68 of the shaft 34, which shaft 34 from the hex portion 68 continues in smaller diameter to form a circular shaft 69 which is free to rock and has a bearing in the member 52, which in turn oscillates or rocks in the bearing 59in the cover plate 48; whereas the shaft 34, previously described, oscillates or rocks in the hollow member 38, which in turn has a bearing gil in the end plate 45. A retainer ring H3 is provided on the end of the shaft 69, whichis held in place by a split ring H fitting into a groove nn the shaft 69, the opposite end of shaft 69 being secured against lateral movement by the key. 43 and the clamp member 35, with the cap-screw partly embedded in the shaft 34 at 12. The hollow member 38 is held in position by the key and the cap-screw 4B, which is partly embeddef.

in the member 38 at 15, and the member El bear-- ing against the cover plate 48. In the construction just described, lateral movement is pre- 

